Many different kinds of ear-worn devices are known in the art. For the purposes of this application, traditional hearing aids, tinnitus maskers, hearables, non-prescription hearing aids, earbuds, hearing protections and others are all encompassed by the employed omnibus term hearing instrument.
Traditional hearing aids are representative for synoptically illustrating structure and function of the entire class of hearing instruments. In this context, several different types of hearing aids are known. Miniature hearing aids that are completely wearable in the ear, e.g. in-the-ear hearing aid (ITE) or completely-in-the-canal hearing aid (CIC), are suitable for countering mild hearing impairment. In order to counter more severe hearing impairment larger devices, worn behind the ear, e.g. behind-the-ear hearing aid (BTE) or receiver-in-the-canal hearing aid (RIE), are normally required. These devices deliver audio data, either as an acoustic wave or as a wired electric signal, to a bell-shaped hearing aid dome that is positioned in the ear of the hearing-impaired person.
Regardless of the type of hearing instrument employed, the ear canal becomes at least partially occluded from the outside environment when the hearing instrument is in use. As a consequence, occlusion effect develops. It is manifested by the hearing instrument wearer perceiving his/her own voice as being hollow and/or becoming unnaturally amplified.
Traditionally, the above-discussed undesirable effects are reduced by introducing a ventilation tube (vent) that establishes fluid communication between the ear canal cavity and the outside environment. As is well-known to the artisan, this solution is still ridden with considerable drawbacks. In an attempt to remedy these, EP2405674 discloses a vent with a resonator. Its resonance frequency range is rather narrow (10-100 Hz) and permanently preset at the factory.
In consequence, some problems associated with the solutions available in the art still persist. This is particularly true in complex and/or fast-changing listening situations.